1. Technical Field
The present invention relates to a vibrator element, a vibrator, an electronic device, an electronic apparatus, and a moving object each using the vibrator element.
2. Related Art
In the past, as a vibrator element for detecting an angular velocity, there has been known a so-called “double-T type” gyro vibrator element (see e.g., JP-A-2006-201011 (Document 1)). The gyro vibrator element described in Document 1 includes a base section, first and second detection vibration arms (detection arms) extending from the base section to the both sides along a y axis, first and second connection arms (connection arms) extending from the base section to the both sides along an x axis, first and second drive vibration arms (driving arms) extending from the first connection arm to the both sides along the y axis, third and fourth drive vibration arms (the driving arms) extending from the second connection arm to the both sides along the y axis, and weight sections disposed respectively on the tip portions of the first and second detection vibration arms and the first through fourth drive vibration arms so as to have a larger width.
In recent years, such a gyro vibrator element as described above has been expanding in application such as portable equipment or on-vehicle equipment. Thus, the range of the temperature environment, in which the gyro vibrator element is used, has been widened, and it has been becoming required to stably operate in a broad temperature range. Further, in addition, miniaturization has also been becoming required.
In such a gyro vibrator element as described above, even in the case of regulating the resonant frequencies fd (Hz) (hereinafter referred to as “driving vibrational frequency fd”) of the first through fourth drive vibration arms to a predetermined value in the room temperature, when the ambient temperature changes to high temperature or low temperature, there occurs a so-called temperature drift such as a resonant frequency fluctuation or a characteristic fluctuation. It has been known that the occurrence of the temperature drift is affected by an unwanted vibration such as a vibration in an out-of-plane flexural vibration mode. In order to suppress the temperature drift, there has been proposed in, for example, JP-A-2008-26110 (Document 2) to set the out-of-plane flexural first-order mode vibrational frequency fs1 as the out-of-plane flexural vibration mode to either one of fd×2.2≦fs1≦fd×2.8 and fd×3.2≦fs1≦fd×3.8.
However, the gyro vibrator element of the related art described above is effective in the relationship between the driving vibrational frequency fd and the out-of-plane flexural mode vibrational frequency fs, but does not have sufficient effect with respect to an unwanted vibration different from the out-of-plane flexural mode, and therefore, further reduction of the temperature drift has been demanded.